1. Field of the Invention
The present invention generally relates to the fabrication of semiconductor devices, and more particularly, to methods for forming a titanium nitride layer on a substrate.
2. Description of the Related Art
Interconnect structures of integrated circuits and semiconductor devices are typically fabricated by forming a series of dielectric layers and conductive layers in order to create a three dimensional network of conductive layers separated by dielectric material. The interconnect structure may be fabricated using, for example, a damascene structure in which a dielectric layer such as a low k dielectric layer is formed atop one or more conductive plugs or sub-layers. In order to form an electrical connection to the conductive sub-layers, the dielectric is patterned and etched to define via openings therethrough. Formation of the via openings within the dielectric layer exposes a portion of the conductive line. Therefore, reliable formation of these interconnect features is an important factor in ensuring the quality, performance and reliability of devices formed on individual substrates and in each die.
Fabrication of such interconnect structures may be achieved by a variety of techniques. A typical method for forming layers for interconnection structure includes physical vapor deposition of a barrier layer over a feature, such as a trench or a via, followed by a physical vapor deposition a metal layer on the barrier layer to fill the feature. Finally, after the deposited material layers, including the metal and the dielectric layers, are formed on the substrate, a planarization or an etching process is performed to define a conductive interconnect feature with desired dimensions on the substrate.
One common material often utilized to fabricate barrier layers is titanium nitride. However, problems may be encountered during conventional processes for fabricating titanium nitride barrier layers. For example, in conventional titanium nitride physical vapor deposition techniques, particles (such as titanium nitride particles) may form during the process within the processing chamber. These particles may become deposited upon the surface of the substrate, thereby undesirably affecting film properties, such as uniformity, voids, or other defects.
Therefore, there is a need in the art for improved methods for forming titanium nitride layers.